Song Request Via Flask

#!/usr/bin/env python3
import json
from flask import Flask, request, redirect
import requests, base64, os.path

username = "YOUR_SPOTIFY_USERNAME"
playlist_id = "YOUR_PUBLICK_PLAYLIST_ID"

app = Flask(__name__)

# Authorization code flow
url = "https://accounts.spotify.com/authorize"
CLIENT_ID = "YOUR_APP_CLIENT_ID"
REDIRECT_URI = "http://127.0.0.1:8080/callback"
SCOPE = "playlist-modify-public"
CLIENT_SECRET = "YOUR_APP_SECRET_ID"

@app.route('/')
def index():
    return redirect(
        "https://accounts.spotify.com/authorize/?client_id=" + CLIENT_ID + "&response_type=code&redirect_uri=http%3A%2F%2F127.0.0.1%3A8080%2Fcallback&scope=" + SCOPE)


@app.route("/callback")
def callback():
    access_token = request.args
    code_payload = {"grant_type": "authorization_code", "code": str(access_token['code']), "redirect_uri": REDIRECT_URI}
    base64encoded = base64.b64encode(bytes(CLIENT_ID + ":" + CLIENT_SECRET, "UTF-8"))
    headers = {"Authorization": "Basic %s" % base64encoded.decode('utf-8')}
    post_request = requests.post("https://accounts.spotify.com/api/token", data=code_payload, headers=headers)
    json_response = json.loads(post_request.text)



    #song = json.loads(open(os.path.dirname(__file__) + '/add_song.json',"r", encoding="utf-8-sig", errors="ignore").read())
    #track_ids = song[u"track"][u"id"]

     track_ids = "TRACK_ID_OF_SONG_YOU_WANT_TO_ADD"


    add_req = requests.post(
        "https://api.spotify.com/v1/users/" + username + "/playlists/" + playlist_id + "/tracks?uris=spotify:track:" + track_ids,
        data=code_payload, headers={'Authorization': 'Bearer ' + json_response[u'access_token']})
    return "Song Added"

if __name__ == "__main__":
    app.run(debug=True, port=8080)